The invention is in the field of readily applicable and removeable clampable sleeve type couplings for effecting joints between pipes and their fittings.
More specifically the coupling of the invention is intended for use with smoth surface pipes and tubing and their fittings as normally used in known and conventional methods of assembly such as threading soldering, glueing, brazing or welding.
There is a need for a simple device to connect pipes to their fittings that is economical, not only to manufacture, but also in actual installation and use.
Such a device, to achieve the greatest economy, must permit easy assembly, equally easy disassembly, and must permit the salvage of the maximum amount of components of the system; this device according to the invention permits the reusage, time after time, of all components provided their integrity is safeguarded.
It is known that disastrous fires were caused, directly or indirectly, by the use of open flame or by the emanation of inflamable fumes and their subsequent ignition during the installation or alteration of plumbing systems; this device according to the invention eliminates these hazards since no flamable components, heat or flame is required for its installation.
It is known that lack of thorough desoxydation and cleaning of the components of plumbing systems requiring soldering or glueing results in weak or leaking joints, which in turn require dismantling and reinstallation, sometimes at the cost of a number of new and extra fittings and material and great expense of time; this device according to the invention does not require such thorough desoxydation and cleaning, resulting in savings of time, because it relies on its composition seal for fluid tightness. Most known systems of pipe joints depend on their purposemade fittings, ordinarily compatible only within their own system, to function and their adaptability to different systems is very limited if non existent; this device according to the invention makes use of fittings normally used with other conventional joining methods without recurring to their hazard prone joining techniques and favors adaptation of this invention with other joining methods wherever tolerances between components permit.
This flexibility permits the creation of hybrid systems where one side is joined conventionally and the other side with the coupling subject of this disclosure.
Most known systems of pipe joints require the use of tools in the assembly and disassembly of the coupling or fitting; this device according to the invention offers the choice between hand or tool operable clamping means, which in hand operable clamping means offers an obvious time saving potential to the user.
First development of the invention revealed a major weakness in its retaining means, which could accidentally be released while the system is pressurized and this condition was also found in Canadian Pat. No. 498,350 to Ferguson Dec. 15, 1953; this undesirable feature is overcome in the device subject of the disclosure as only willfull release of the retainer sleeve, while the system is pressurised, may result in loss of fluid tightness.
Some known systems of pipe joints depend on grooves in the pipe ends to mechanically secure the pipes to their fittings, said grooves being ordinarily square edged in profile to ensure more positive and non slip contact of retaining lugs; the device according to the invention makes similarly use of a groove in the end of the pipe and of the fitting to ensure a positive grip of the lugs both on the pipe and on the fitting end in a very different way as explained hereafter.
This groove must be distinguished from the gasket seating groove whose function is solely related to the fluid tightness of the system, this first mentioned groove shall be called slip resisting groove as opposed to the gasket groove.
The slip resisting groove need not be square in profile but may be of any profile suitable to provide slip resistance for the lugs of the retainer sleeve; depending on the pipe or fitting material this slip resisting groove can be square, V shaped or rounded according to the characteristics of the pipe or fitting material and the easiest method of forming such groove. The profile of the slip resisting groove is dictated by the stress characteristics of the material of the pipe and/or fitting; a rounded groove profile offers the benefit of minimizing the occurrence of localized stress points, ordinarily found to be the cause of failure, and provides an infinity of contact planes parallel to the end plane of the lugs; this is particularly important as it provides automatic adjustment for varying lug angles relatively to the pipe longitudinal axis, specially under varying pressure loads.
It is known that soldered fittings can be unsoldered only when the fitting and the pipe adjacent thereto are completely drained; since the device according to the invention does not require any heat in order to be removed but only unlocking of the retainer sleeve, it is now clear that no time is wasted draining the system.
This feature of easy removal leads to other potential economies since any such retainer sleeve used in conjunction with a end cap or any other type of fitting at low points of plumbing systems will act as low cost drains. Further research led to the present disclosure wherein a combination of the above described and some other desirable features are incorporated.
The device and system according to the invention consist of the following:
1. a clampable one piece split retainer sleeve, PA1 2. a hand or tool operable clamping means, PA1 3. a sealing gasket of known design and composition, PA1 4. a rounded groove in the pipe end to seat the sealing gasket, PA1 5. a slip resisting groove in the end of the pipe and of the fitting where such a groove is required by the nature of the pipe and/or fitting.